rx.singles.BlockingSingle Maven / Gradle / Ivy
/**
* Copyright 2015 Netflix, Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package rx.singles;
import rx.Single;
import rx.SingleSubscriber;
import rx.Subscription;
import rx.annotations.Experimental;
import rx.internal.operators.BlockingOperatorToFuture;
import rx.internal.util.BlockingUtils;
import java.util.concurrent.CountDownLatch;
import java.util.concurrent.Future;
import java.util.concurrent.atomic.AtomicReference;
/**
* {@code BlockingSingle} is a blocking "version" of {@link Single} that provides blocking
* operators.
*
* You construct a {@code BlockingSingle} from a {@code Single} with {@link #from(Single)}
* or {@link Single#toBlocking()}.
*/
@Experimental
public class BlockingSingle {
private final Single single;
private BlockingSingle(Single single) {
this.single = single;
}
/**
* Converts a {@link Single} into a {@code BlockingSingle}.
*
* @param single the {@link Single} you want to convert
* @return a {@code BlockingSingle} version of {@code single}
*/
@Experimental
public static BlockingSingle from(Single single) {
return new BlockingSingle(single);
}
/**
* Returns the item emitted by this {@code BlockingSingle}.
*
* If the underlying {@link Single} returns successfully, the value emitted
* by the {@link Single} is returned. If the {@link Single} emits an error,
* the throwable emitted ({@link SingleSubscriber#onError(Throwable)}) is
* thrown.
*
* @return the value emitted by this {@code BlockingSingle}
*/
@Experimental
public T value() {
final AtomicReference returnItem = new AtomicReference();
final AtomicReference returnException = new AtomicReference();
final CountDownLatch latch = new CountDownLatch(1);
Subscription subscription = single.subscribe(new SingleSubscriber() {
@Override
public void onSuccess(T value) {
returnItem.set(value);
latch.countDown();
}
@Override
public void onError(Throwable error) {
returnException.set(error);
latch.countDown();
}
});
BlockingUtils.awaitForComplete(latch, subscription);
Throwable throwable = returnException.get();
if (throwable != null) {
if (throwable instanceof RuntimeException) {
throw (RuntimeException) throwable;
}
throw new RuntimeException(throwable);
}
return returnItem.get();
}
/**
* Returns a {@link Future} representing the value emitted by this {@code BlockingSingle}.
*
* @return a {@link Future} that returns the value
*/
@Experimental
public Future toFuture() {
return BlockingOperatorToFuture.toFuture(single.toObservable());
}
}